The action of 7-N-(p-hydroxyphenyl)mitomycin C [M-83] in suppressing murine immune response.

The immuno-suppressive activities of 7-N-(p-hydroxyphenyl)mitomycin C [M-83], a derivative of mitomycin C (MMC), which has better antitumor activity against murine tumors, was investigated in mice. A single injection of M-83 induced an apparent but relatively transient reduction in both plaque-forming cell production and delayed type hypersensitivity reaction to sheep red blood cells. The suppressive effect of M-83 was significantly milder than that of MMC at the same effective and molar equivalent doses. Moreover, the recovery from immunosuppression induced by M-83 was also relatively rapid as compared with MMC. The inhibiting activity of M-83 against the blastogenic response of spleen cells was milder in vivo, but was more significantly cytotoxic in vitro than that of MMC.